# V639 Herculis
**Wikidata**: [Q91819561](https://www.wikidata.org/wiki/Q91819561)  
**Source**: https://4ort.xyz/entity/v639-herculis


## References

1. SIMBAD
2. VizieR
3. Near-infrared metallicities, radial velocities, and spectral types for 447 nearby M dwarfs
4. An activity-rotation relationship and kinematic analysis of nearby mid-to-late-type M dwarfs
5. Washington Double Star Catalog
6. The rotation and galactic kinematics of mid M dwarfs in the solar neighborhood
7. VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
8. Fourth USNO CCD Astrograph Catalog
9. Gaia Data Release 2
10. Trumpeting M dwarfs with CONCH-SHELL: a catalogue of nearby cool host-stars for habitable exoplanets and life
11. CARMENES input catalogue of M dwarfs. III. Rotation and activity from high-resolution spectroscopic observations